Conventionally, an air spring which utilizes compressed air's elasticity has been known. An example of a conventional air spring is described for example in Japanese Patent Laying-Open No. 2000-035075. The air spring described in this document has a level adjustment mechanism for keeping compressive deformation (or stroke) substantially constant.
As another example of a conventional air spring, there is also an air spring described in Japanese Patent Laying-Open No. 2012-017769. The air spring described in this publication is a stopper equipped air spring comprising a descent regulating means. As a still another example of a conventional air spring, an air spring described in Japanese Patent Laying-Open No. 2012-145135 can be mentioned. This air spring is equipped with a stopper for limiting an amount of vertical displacement.